Stable metal-organic frameworks based mixed matrix membranes for Ethylbenzene/N2 separation

Abstract To remove volatile organic compounds (VOCs) from air, N2 or other waste gas streams in industrial processes is significant to the environmental protection and human health, as well as gain the opportunity to reuse these valuable chemicals. Mixed matrix membranes (MMMs) based on metal-organic frameworks (MOFs) have been proved to have potential application in this field. In this work, MIL-101 and UiO-66 are selected to construct MMMs for efficient ethylbenzene separation because of following factors: (1) the high ethylbenzene adsorption capacities; (2) the three-dimensional channels with large pore size; and (3) the ideal hydrothermal stability of structures. MIL-101@Pebax and UiO-66@Pebax MMMs have been prepared in an environment-friendly way and evaluated for the ethylbenzene/N2 separation performance. SEM, TGA, FITR and XRD results indicate that continuous MMMs with different filler loading ratios have been fabricated successfully. The results show that MIL-101@Pebax and UiO-66@Pebax with the MOF loading radio of 20 wt% possess ethylbenzene/N2 permselectivity of 284 and 100 respectively at 25 °C, 0.05 MPa and moderate feed ethylbenzene concentration (1000 ppm), which increased by 10.5 and 3.0 times compared with the pristine Pebax membrane. Effects of upstream pressure, feed concentration, and operating temperature on separation performance have been investigated for ethylbenzene/N2 separation. Due to the selective adsorption capacity to ethylbenzene, as well as the large pore size of MIL-101(Cr), MIL-101@Pebax can be applied as efficient membrane materials in ethylbenzene capture system for high concentration region at ambient temperature.